The present invention is directed to fibrous nonwoven webs with uniform, directionally-oriented projections located on at least one surface of the formed material as well as the process and apparatus for making such a material.
Disposable products are an ever increasing portion of the consumer market, especially in the context of personal products such as cleaning products for the face and body. The same is true for products used for household cleaning and other cleaning applications. A commonly desired attribute for all such products is the cleaning ability of the product and its ability to absorb and retain fluids. Today there are many wiping products that are available in either a dry or wet state. A large number of such products are relatively flat, two-dimensional products with little variability in the topography of the material. Other materials are textured due to embossing of the wiping material. Still other materials are tufted. See, for example, U.S. Patent Application No. 2003/0211802 to Keck et al. assigned to Kimberly-Clark Worldwide, Inc. which discloses three-dimensional coform nonwoven coform webs which have projections which increase the bulk of the nonwoven web and aid in the scrubbing and cleaning ability of the coform web. See also U.S. Pat. No. 5,180,620 to Mende assigned to Mitsui Petrochemical Industries, Ltd. which discloses a nonwoven fabric comprised of meltblown fibers with projections extending from the fabric base. Still a further example is U.S. Patent Application No. 2007/0130713 to Chen et al. and assigned to Kimberly-Clark Worldwide, Inc. which discloses a cleaning wipe with a textured surface which may be used as a stand-alone product or can be incorporated into a cleaning tool. The wipe includes a base material having an application face and a plurality of projections extending generally transversely from the application face. The projections may have various shapes, including a mushroom shape. A high friction element can be applied to at least a portion of the projections to provide enhanced abrasive scrubbing functionality. With the mushroom-shaped embodiment the projections have a cross-sectional shape such that the head portion extends laterally beyond and overhangs the base portion. The voids or spaces between the projections are said to be particularly well suited for trapping hair and other difficult to retain materials from the surface being cleaned. The tapered voids (tapered from the head portion of the projections towards the land areas) allow for hair and other relatively larger particulate matter to become essentially “wedged” into the void spaces, with the tapered profile of the projections serving to “lock” the particulate matter within the voids. Yet another example of a material with a three-dimensional shape is disclosed in U.S. Patent Application No. 2002/0132544 to Takagaki assigned to Toyoda Boshoku Corporation which spins semi-molten fibers onto a mold. U.S. Pat. No. 6,610,173 to Lindsay et al. assigned to Kimberly-Clark Worldwide, Inc. discloses a method for imprinting a paper web during a wet pressing event with asymmetrical protrusions corresponding to the deflection conduits of a deflection member. In certain embodiments, if substantial shear is applied to the deflection members by way of differential velocity transfer, a snowplow effect can be produced in which the moist fibers are sheared and piled up toward one side of the protrusion.
Despite the foregoing examples of products and processes for creating such textured materials, there is still a need for materials that are textured and easy to produce. The present invention is directed to a material which has protrusions which are directionally-oriented in one direction in a uniform manner. In so doing, the projections can act to provide more friction when wiped across a surface in one direction than in another. As a result, the material will have a somewhat rougher feel when wiped in one direction and a smoother feel in the opposite direction. Also disclosed is a process and apparatus for making such a material.